Flat feet or pes planus is a common orthopedic condition that may lead to significant pain and deformity in the foot. Flat feet is an absence or low lying arch on the inner side of the foot.
The main functions of the foot are to support the body weight and lever the forward motion of the body. To help this function, the foot is made of a series of small bones with supporting arches/springs.
The arches of the foot help to distribute the body weight equally among the entire foot. A curve on the inner side of the foot prevents the nerves and blood vessels from compression. A proper arch also maintains the dynamic properties of the foot during walking.
The inner arch acts like a bridge with the wedge shape of the bones helping to form the concavity. The plantar and spring ligament act as staples holding the bones together. The small muscles of the foot and plantar aponeurosis acts as a tie-beam. The posterior tibial tendon, anterior tibial tendon, and the deltoid ligament act as slings.
More than 2/3rd of the adults have a flexible flat foot. In the case of flexible flat feet, the arch collapses only on standing or weight-bearing. Flexible flat feet are generally asymptomatic and may require no treatment. Rigid flat feet have an absent arch on both non-weight bearing and weight-bearing.
Flat feet may be associated with other inherited diseases. Diseases such as Marfan’s syndrome, Ehler danlos syndrome, down’s syndrome, congenital vertical talus, and tarsal coalition are commonly associated.
Acquired causes of the flat foot are arthrosis (arthritis of a small part of the joint) after injury. After treatment of clubfoot, and tight tendon Achilles due to gout or rheumatoid arthritis. Rigid flat feet are associated with neuromuscular conditions and cerebral palsy.
Most patients are initially asymptomatic but may develop significant deformities and altered gait after years. Patients may complain of foot pain and burning sensation in the foot. The pain becomes significantly worse after standing and walking for long.
The patients walk in a clumsy manner and avoid lifting the heel off the ground while walking. They may walk lifting the entire foot together off the ground.
The Achilles tendon may become tight causing worsening of flat feet and deformity. The patients in many years may end up with severe arthritis of the feet. Flat feet patients are prone to develop Achilles tendonitis, plantar fasciitis, bunion, etc.
Flat feet are normal in children up to 3 years of age, after which the arches develop. The most common age group affected is adolescents and young adults. The diagnosis is made by a doctor’s visit after a thorough examination.
The foot is examined along with other joints to look for any inherited diseases. The fallen arches of the foot are examined on standing and without weight-bearing.
Clinical tests designed to check the arch are performed. The range of motion of the upper, mid, and lower foot is examined. The Achilles tendon is examined to look for any tightness.
Radiological examination is done in the form of an X-ray to look for bony deformities. A CT scan may be used to look for fused tarsal bones. MRI can provide detail of the tendons, ligaments, and other soft tissues.
Flexible flatfoot may be asymptomatic, not requiring any treatment. Physical therapy and home exercises may be recommended to increase the arch and prevent future deterioration. Nonsteroidal anti-inflammatory drugs may be used to relieve pain.
Arch supports in the form of felt pads, or rubber sponge may be used to support the inner arch. Special braces may be used to hold the heel bone in the desired position. Special shoes and heel inserts can also be used.
Exercises are aimed to strengthen the foot muscles and stretch the Achilles tendon with calf muscles. Examples of flat feet exercises are grasping marbles with the toes, walking on toes, and walking in the sand.
Surgical management is done in rigid flat feet and in flexible flat feet with complications. The surgeries are aimed at lengthening the Achilles tendon, cutting and fusing the bone in the desired position.